Study On Mechanical Properties And Energy Absorption Characteristics Of Foam Metal Filled Steel Tube Components

Thin-walled metal tube can be used for a structural energy dissipative member,which has the characteristics of light weight and simple manufacturing process,and has been widely used in the automobile manufacturing,construction industry,aerospace and other fields.The energy dissipation of thin-walled metal tube is accomplished by plastic deformation of the component itself.However,due to the lack of lateral constraints,the deformation range of thin-walled metal tube is large and prone to local instability.With the growing maturity of foam metal manufacturing technology,the practical application of foam metal which poesses the advantages of small density,small Poisson’s ratio and stable deformation under compression has been developed rapidly.Whereas,the foam metal is difficult to be applied alone because of its poor tensile and flexural properties.The thin-walled metal filled with foam metal can give full play to the advantages and of the two materials,and is an ideal and efficient energy absorbing member.In this paper,the load-bearing capacity,deformation mode,stress distribution and energy absorption characteristics of empty steel tube and foam metal-filled steel tube members under axial quasi-static load were investigated by means of experiment and numerical simulation.The main works are as follows:(1)The experimental study of foam metal-filled steel tube members is carried out.Taking the length of members and the thickness of the steel tube as analysis parameters,the test results are summarized from two aspects of bearing capacity and deformation.The results between the quasi-static axial compression test of empty steel tube and foam metal-filled steel tube are compared and analyzed.The results show that the axial force-displacement curve and the failure mode obtained from the numerical simulation agree well with the experimental results,which validates the correctness of the numerical simulation model and effectively provides a foundation for the abundant parametric anlysis of numerical simulation.(2)The numerical simulation of empty steel tube components and foam metal-filled steel tube components under quasi-static axial compression is carried out.Taking the length,thickness of tube,section and side length of the specimens as variable parameters,the mechanical performance of these two kinds of members is compared from the aspects of bearing capacity,deformation,stress distribution and energy absorption.The results show that the bearing capacity and total energy absorption of foam metal-filled steel tube under quasi-static axial compression are higher than that of empty steel tube.The bearing capacity of these two members decreases with the increase of length,and increases with the increase of wall thickness,section and side length.The deformation of foam metal-filled steel tube is more regular and dense than that of empty steel tube.The large stress area also decreases.(3)The mechanical properties and energy absorption properties of foam metal-filled steel tubes with initial geometric imperfections under quasi-static axial compression are studied.The finite element numerical models of different defect sizes in the form of single point,diagonal point,same-edge point and three-point defect are established.The different performances of those members are inverstigated from the aspects of bearing capacity,deformation and energy absorption characteristics.The results show that the first peak load decreases with the increase of defect size,wheras the corresponding displacement load increases.The deformation range of diagonal defect is the largest,and the peak load and total energy absorption after deformation are also the largest.